Flange sleeve, method for the production thereof and bending tool for producing flanges on a sleeve

ABSTRACT

A flanged bush for plain bearings having at least one flange formed thereon having axially facing inner and outer surfaces and including at least one metallic layer. The flange includes material-displacing recesses impressed axially into said flange in said metallic layer at least two points distributed over said flange in a circumferential direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/467,701 for a FLANGE SLEEVE, METHOD FOR THE PRODUCTION THEREOF ANDBENDING TOOL FOR PRODUCING FLANGES ON A SLEEVE, filed on Dec. 8, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a flanged bush, in particular a flanged bushfor plain bearings with at least one flange formed thereon, according tothe precharacterizing clause of claim 1, a method for the productionthereof according to the precharacterizing clause of claim 9 and abending die according to the precharacterizing clause of claim 13.

2. Description of Related Prior Art

Flanged bushes, which comprise either one or two flanges, are known in avery wide range of sizes, with diameters ranging from centimeters todecimeters. The materials used depend on the intended application,wherein the bush material may be of single- or multilayer construction.Single-layer bushes are known as solid bushes. Bushes of multilayerconstruction generally comprise a backing material and an overlay. Theoverlay may consist of a metal alloy or plastics. The invention relatesto all flanged bushes, irrespective of their dimensions, intendedpurpose and the materials used, with the one reservation that theflanged bushes have to comprise at least one metallic layer.

To produce flanged bushes, an edge of prefabricated bearing sleeves orbushes is bent into a flange in a secondary operation. A conventionalmethod is bush wrapping, wherein a flat strip portion, the so-calledblank, is wrapped round to form a bush or sleeve.

In the case of wrapped bearing bushes, it is generally necessary for thebutt joint to be closed when the bush is fitted, while the butt joint isgenerally not fully closed when the bearing bush is not fitted, sincethe material springs open to a greater or lesser degree depending on themethod used to produce the bush 9c.f. DIN 1494, part 1, Jun. 1983, p.1).

Production methods for wrapped bushes are known and are described forexample by Dipl.-Ing. Hugo Kotthaus in ‘BetriebstechnischesTaschenbush”, vol. 2, 7^(th) edition, Karl Hanser Verlag Munich, 1967,pp. 212ff.

To close open butt joints, it is proposed in DE-OS 23 17 564 to heat thebushes and simultaneously to prevent an increase in diameter as a resultof thermal expansion.

Both with this known method and with a shaping method described in DE-PS517530, is it possible to close the butt gap in bushes.

However, if such prefabricated bushes are shaped into flanged bushes, bybending the edge of the bush, the butt joint opens up again, wherein thegap width may assume considerable dimensions depending on the diameterand flange width.

Flanged bushes with gaps can only be fitted using special tools, withwhich the flanged bush is compressed through the application ofconsiderable force, wherein the flanged bush may possibly also warp,causing damage to the flanged bush.

Relatively small flanged bushes, which are transported in large numbersin cartons as loose cargo, may become hooked together, often resultingin a chain of several flanged bushes. The buyer has to separate theflanged bushes laboriously and generally by hand before fitting them.There has therefore long been a desire for flanged bushes with closedbutt joints.

In flanged bushes, a closed butt joint could only be achieved by weldinga ring forming the flange to a bush. The disadvantage of this method isthat welding is more expensive than bending of the bush edge.

SUMMARY OF THE INVENTION

It is therefore the object of the invention to provide a bush withclosed or extensively closed butt joint which does not cost any more toproduce than the conventional flanged bushes obtained by bending.

A further object of the invention is to provide a suitable method and anappropriate device or bending die.

As far as the method is concerned, the object is achieved in that, atleast two points distributed around the flange in the circumferentialdirection, material-displacing recesses are formed at least in the metallayer of the flanged bush.

It has surprisingly been demonstrated that the material displacementcaused by the formation of the recess stretches the flange in thecircumferential direction in such a way that the butt gap is closed.

The formation of material-displacing recesses is a cost-effectivemethod, especially if the recesses are produced, as preferred, bystamping.

The recesses may be formed in the inner and/or outer surface of theflange. Where the recesses are formed depends on the structure of theflanged bush, the material and the intended application. If the flangedbushes are intended for diesel engines, for example, the bush consistsas a rule of a metallic backing material, on which at least one overlayhas been applied. In order not to damage the overlay by the formation ofmaterial-displacing recesses, the recesses are preferably formed in theinner surface of the flange.

If, in the case of coated bushes, the recesses are to be formedadditionally or solely in the outer surface of the flange, the recesseshave to extend into the metallic backing layer, since otherwise notenough of the material causing the springing-open effect is displaced.

The recesses are preferably produced when bending the bush edge.Incorporation into the bending process has the advantage that noadditional method step is necessary, such that the production costs donot increase relative to conventional flanged bushes. If thematerial-displacing recesses are formed in the flange during bending,the butt joint cannot open in the first place.

Closure of the butt joint may be controlled or the width of the buttjoint may be specifically adjusted, depending on the intended purpose ofthe bush, by means of the size, number, shape and depth of the recesses.

The flanged bush according to the invention, which comprises no butt gapor comprises a specifically adjusted butt gap, is characterized in thatthe flange comprises material-displacing recesses at least in themetallic layer at least two points distributed over the flange in thecircumferential direction.

The recesses preferably take the form of impressions, and are preferablylocated in the inner and/or outer surface of the flange. In a furtherpreferred embodiment, the recesses extend as far as into the outer edgeof the flange. It has been demonstrated that the material-displacingrecesses are most effective, the further they are formed towards theoutside, when viewed in the radial direction. The number of recesses maybe markedly reduced relative to the number of recesses which do notextend as far as into the outer edge of the flange. The recessespreferably widen radially form the inside to the outside. In this way,greater material displacement is caused where the circumference becomeslarger. The recesses are preferably semicircular or wedge-shaped.

As an alternative or in addition to the widening of the recesses, it isadvantageous for the recesses to increase in depth form the insideradially towards the outside, because the associated increase inmaterial displacement takes account of the radially outward increase incircumference. The recesses preferably extend radially over the entirewidth of the flange.

The bending die according to the invention is characterized in thatelevations are provided at least two points distributed over the endface in the circumferential direction of the end face. The elevationsare preferably arranged equidistantly in the circumferential direction.The elevations may exhibit a circular, oval or wedge-shaped structure.It is also possible for the elevations to take the form of radiallyextending webs. The elevations may be formed on the end face or take theform of exchangeable components which are inserted into the end face.Punches projecting relative to the end face are preferably inserted intothe end face. The punches which may be inserted are preferably pins,which are inserted into corresponding drill holes in the end face of thebending die. It is thereby possible to arrange the bending die invariable ways, and thus, to adapt it to various widths of flanges, thediameter of the flanged bush remaining the same.

The bending device according to the invention comprises a bending dieand a pressure plate acting on the bush edge to be bent, wherein thebending die and/or the pressure plate comprise elevations on the surfacefacing the bush edge.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will be readily appreciated as thesame becomes better understood by reference to the following detaileddescription when considered in connection with the accompanying drawingswherein:

FIG. 1 shows a conventional flanged bush with a flange according to theprior art,

FIG. 2 is a plan view of a first embodiment of a flanged bush accordingto the invention,

FIG. 3 is a plan view of a further embodiment of a flanged bushaccording to the invention,

FIG. 4 is a plan view of a further embodiment of a flanged bushaccording to the invention,

FIG. 5 shows a section through the flanged bush shown in FIG. 4, alongline V-V,

FIG. 6 shows a section through a flanged bush according to a furtherembodiment,

FIG. 7 shows a vertical section through a bending device, and

FIG. 8 is a plan view of a bending die with flanged bush insertedtherein.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

FIG. 1 shows a conventional flanged bush 1, which comprises acylindrical bush body 2 and a single flange 3 formed thereon, havingbeen produced by bending of the bush edge. As a result of the productionprocess, the flanged bush 1 comprises a considerable butt gap 5.

FIG. 2 is a plan view of a flanged bush 10 according to the invention,produced by the method according to the invention. This flanged bush 10likewise has a cylindrical bush body 12 and a single flange 13, whichcomprises material-displacing recesses 16 on the inner surface 14 of theflange 13 at a plurality of equidistant points in the circumferentialdirection. In the embodiment of FIG. 2 shown here, thematerial-displacing recesses are semi-circular in form, such that therecesses widen radially form the inside outwards. The recesses areapplied in such a way that they extend as far as into the outer edge 15of the flange 13. The flanged bush 10 exhibits a closed butt joint 11.

FIG. 3 is a plan view of a flanged bush 10 according to a furtherembodiment. In contrast to FIG. 2, the material-displacing recesses 16′are wedge-shaped and extend over the entire width of the flange. Thewedge-shaped or V-shaped configuration of the recesses 16′ likewisewidens radially form the inside outwards.

FIG. 4 shows a further embodiment of a flanged bush 10, wherein theequidistantly arranged material-displacing recesses 16″ are rectangularin plan view. The special feature of these material-displacing recesses16″ is that the depth of the recesses increases radially from the insideoutwards. This is visible in FIG. 5, which shows a section along lineV-V of the flanged bush shown in FIG. 4. The flanged bush shown in FIG.5 has a metallic backing material 17 and an overlay 18, which is appliedto the outer surface 19 of the flanged bush. The recesses 16″ are formedon the inner surface 14 of the flange 13, such that the overlay 18 isnot impaired.

FIG. 6 is a sectional view of a further embodiment of a flanged bush.The bush is again a two-layer flanged bush, wherein, however therecesses 16′″ are formed in the outer surface 19 of the flange 13. Therecesses extend so far into the flange material that the materialdisplacement affects the metallic backing material 17.

FIG. 7 shows a vertical section through a shaping device 20, whichconsists substantially of an upper pressure plate 21, a bending die 22and a lower pressure plate 23. Instead of a lower pressure plate 23, thebending die 22 may also comprise a shoulder inside the bush receptacle25, on which rests the lower end face of the bush. In a first methodstep, the flange 13 may be pre-bent in the manner illustrated here, suchthat only secondary, or post-bending must be performed with the pressureplate 21. The flange 13 is bent in the direction of the arrows, suchthat the inner surface 14 is pressed onto the elevations 24 arranged onthe end face 26 of the bending die 22, thereby forming thematerial-displacing recesses.

In the embodiment shown here, the elevations 24 are web-shaped in formand extend radially over the entire width of the end face 26 of thebending die 22. It is thereby possible to provide flanged bushes havingflanges 13 of different widths with the material-displacing recessesaccording to the invention, without the bending die 22 having to beexchanged or reset. The wide arrows indicate the pressing direction, ifthe shaping device 20 is arranged in a press for example.

FIG. 8 shows a plan view of a bending die 22 with an already shapedflanged bush 10. In the case of this bending die, the elevations 24 areformed by pins 27 inserted into the end face 26. This die may, forexample, be used to produce the flanged bush shown in FIG. 2.

While the invention has been described with reference to an exemplaryembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

1. A flanged bush for plain bearings having at least one flange formedthereon having axially facing inner and outer surfaces and including atleast one metallic layer, wherein the flange includesmaterial-displacing recesses impressed axially into said flange in saidmetallic layer at least two points distributed over said flange in acircumferential direction.
 2. A flanged bush according to claim 1,wherein said recesses are located on said inner surface of said flange.3. A flanged bush according to claim 1, wherein said recesses arelocated on said outer surface of said flange.
 4. A flange bush accordingto claim 1, wherein said recesses are formed in said inner surface andsaid outer surface of said flange.
 5. A flanged bush according to claim1, wherein said recesses extend to an outer peripheral edge of saidflange.
 6. A flanged bush according to claim 1, wherein said recesseswiden circumferentially in a direction radially outwardly of said bush.7. A flanged bush according to claim 1, wherein said recesses have agenerally semicircular shape.
 8. A flanged bush according to claim 1,wherein said recesses have a wedge shape.
 9. A flanged bush according toclaim 1, wherein said recesses have a width that increases axially in adirection radially outwardly of said bush.
 10. A flanged bush accordingto claim 1, wherein said recesses extend radially over the entire widthof the flange.
 11. A bending die for producing one or two radiallyextending flanges having predetermined thicknesses and axially facinginner and outer surfaces on a bush, having a bush receptacle, wherein atleast one end face surrounding the bush receptacle presents a bearingsurface for the flange, and wherein said end face includes comprisesaxially extending elevations at least two points distributed over saidend face in a circumferential direction of said end face having a heightwhich is less than half said thickness of said flange or flanges forimpressing recesses axially into at least one of the inner or outersurfaces.
 12. A bending die according to claim 11, wherein saidelevations are arranged equidistantly in said circumferential direction.13. A bending die according to claim 11, wherein said elevations have acircular contour.
 14. A bending die according to claim 11, wherein saidelevations have an oval contour.
 15. A bending die according to claim11, wherein said elevations have a wedge shaped contour.
 16. A bendingdie according to claim 11, wherein said elevations comprise radiallyextending webs.
 17. A bending die according to claim 11, wherein saidelevations are formed on said end face.
 18. A bending die according toclaim 11, including punches projecting relative to the end face insertedinto the end face.
 19. A bending die according to claim 18, wherein saidpunches comprise pins.
 20. A bending device comprising a bending die anda pressure plate adapted to act on a bush edge to be bent around saiddie to form a flange having a thickness and inner and outer axiallyfacing surfaces wherein one of said bending die and pressure platecomprises elevations provided on a surface facing at least one of theinner or outer surfaces and where said elevations have a height that isless than half the thickness of said flange.